Locking means for electrical apparatus



P 16, 1930. E. WANAMAKER 09 LOCKING MEANS FOR ELECTRICAL APPARATUS Filed Dec. 17, 1927 Patented Sept. 16, 1930 uNITEosrATes 'PAT'ENT OFFICE ERNEST ,WANAMAKER, or CHICAGO, ILLINOIS, ASSIGNOR To KnLr 'rnnn'rrnoor LAM? COMPANY, OF CHICAGO, TLLINOIS, .A CORPORATEOH- OF ILLINOIS ,7 1

LOCKING MEANS roaELncrnIcAL ArPARArUs Application filed December 17, 1927. Serial No. stare-55.

This invention relates to locking means or devices for locking electrical apparatus within supporting sockets and has particular reference to devices of this character forrencler ing electric lamp bulbs, plug fuses, and the like, theftproof.

The subject matter of this invention comprises a theftproof electric lamp so made that it may be inserted in a socket of the usual Fig. 2 is a central sectional view through the base of a lamp embodymg th1s invention and showing the parts in assembled relationship; and

Fig. 3 is a detailed sectional view of a portion of the lamp base member and shell contact.

In general, the invention as illustrated comprise an electric lamp bulb, 10, of standard construction, a base member, 11, adapted to be securely cemented upon the stem or neck, 12, of the lamp bulb and a threaded shell contact, 13, for embracing the base member, 11. 7

It will be understood that I do not desire to restrict the application ofmy invention to its use with lamp bulbs, since various other types of electrical apparatus, such as plug fuses, therm'o ionic valves, and the like, may be substituted for the lamp bulb, 10, and rendered theft-proofin accordance with this invention.

The base member, 11, may comprise a cylindrical shell contact, 14, upon which the threaded shell contact, 13. is loosely fitted. The shell contact, 14, may be secured to the shell contact, 13, by the use of one or more had to a flanged edge, 16, on the threaded areas of adhesive material, as at15, for the purposeof initially fixing the shell contact against rotation relative to the lamp base and lamp.

It will be member, 11, isrotated as by. grasping the bulb, 10, for inserting the lamp into a receptacle, the shell contact, .13, will also be rotated because of the adhesive connections,

15. In this manner, the threaded shell con-.-

tact may be screwed into the receptacle. The lamp or other electrical apparatus may be thus inserted and removed from the receptacle as often as desired, as long as no abnormal rotational forces are exerted thereon. However, Whenit is desired to render the device theftproof, thethreadedshell contact may be screwed home in a receptacle and then if an abnormal and additional force is exerted to screw the device further lIlWaIClly, the adhesive area or; areas as at 15 w1ll be disrupted. Thereafter, the shell contact 13 will be free for rotational movement in respect to the base member 11 and, accordingly, whenan attempt is made to remove the lamplfrom its receptacle by turning the bulb the base member, 11, will merely freely rotate within the threaded shell contact and without exerting rotational force upon such contact. Hence, the bulb or other apparatus, to gether with the base member, 11, will be merely rotated and cannot be removed. I

After the lamp or other electrical apparatus has become worn out so that it isdesirable to remove the same, the operator may place a canvas or other bag over. the glass portion of the lamp and thereupon break the lamp. I The canvas bag will retain the particles of broken glass. Access may then be shell contact for removal thereof by the use oi pliers or othersuitable tools.

-The threaded shell contact, 13, may be permanently retained against longitudinal move .ment in respect to the lamp bymeans of the flange, 16, at the lower-edge of the contact and a flange, 17, at the upper ed 'e or endthereof. The flange, 16, is adapted to be spun over'and tov abut a beadedportion, 18, formed upon the base member near its lower observed'that when the base edge. The flange, 17, is adapted to be spun over a flange portion, 19, at the upper edge of the base member, 11.

From an inspection of Fig. 2, it will be observed that the lower portions of the flange, 16, may be located at a point which will be well within the receptacle member in which the lamp may be inserted. In this way, the receptacle member serves to prevent access to the threaded shell contact member and accordingly this member cannot be turned either inwardly or out of the receptacle by tampering while the lamp or other electrical apparatus is in operative condition.

As shown in Fig. 2, the interior of the base member, 11, may be filled with a suitable cement to cement the base member to the neck of the bulb in the conventional manner. At the upper end of the base member, 11, a center contact, 20, may be positioned and held in place by the use of an insulating end piece, 21, which may be tightly fitted or molded into the upper end of the base member, 11.. Lead wires, 22 and 23, from the lamp filament or other electrical devices may be electrically connected to the contacts, 13 and 20, respectively, in any suitable and well known manner.

It will be noted that the areas of adhesive material, 15, as illustrated may be relatively small so that the same may be readily disrupted by a proper force of relative rotation of the base member and the contact 13. The exact dimensions of the areas of adhesive of course will depend on the strength of the adhesive material used. In order that the adhesive after disruption will not accumulate in quantities at one point between the two contacts, and cause sticking or binding of one contact in respect to the other when it is desired that the lamp be freely rotatable, I find it to be preferable to use a non-granular adhesive such as an animal or vegetable glue of good quality, or a water glass cement or other cementitious and preferably non-granular cement which may be applied and dried to form a highly tenacious thin film between the adjacent metallic surfaces of the contacts. As indicated in the drawings, the areas of adhesive are preferably applied adjacent the outer edges of the contacts so that after disruption the film particles in the adhesive will drop out of the device and not tend to accumulate and cause binding or jamming of the then rotatable bulb. Hence after disruption of such adhesive, no further resistance will be offered to the free turning of the bulb parts in respect to the threaded shell contact. Relatively thin liquid adhesives, for example as those above mentioned, are preferably used in order that the same may be uniformly applied and dried in firm adhering relationship with the intended areas, thus providing connections which may be uniformly disrupted by predetermined forces.

Vhile I have described my improvements in detail and in connection with a preferred form thereof, I do not desire to be limited to such details or forms, since many changes and modifications may be made and the invention embodied in various different forms without departing from the spirit and scope of the invention in its broader aspects. Therefore, I desire to cover all modifications and forms coming within the language or scope of the appended claim.

What I claim as new and desire to be secured by Letters Patent of the United States is:

In combination, an enclosure for electrical apparatus, a cylindrical shell mounted on said enclosure, means for preventing unauthorized removal of the enclosure from the shell, said shell being provided with means for engaging a supporting receptacle by turning movement of said shell, and a film-like layer of nongranular adhesive iniially fixing said enclosure against rotation with respect to said shell to normally permit insertion and removal of the shell with re spect to a receptacle by turning said enclosure, said adhesive being purposely designed to be disrupted by the exertion of a predetermined force in the direction of further inward turning of the enclosure after seating of the same in the receptacle.

in testimony whereof I have signed my mine to this aecification.

ERNEST WANAMAKER.

ltd) 

